• Journal of Navigation and Port Research
• /
• v.39 no.3
• /
• pp.233-239
• /
• 2015

Recently, Due to variable marine accident occurred, problems relating to marine accidents have been raised. Of these accidents, designated anchorage of Korea coastal port, spcially open-sea anchorage, occurred dragging anchor and accidents are likely, due to failure to obtain a valid ship's holding power so that it is the situation unsatisfactory that ensuring the safety of the anchored ship and anchorage systematic safety management stadars for the efficent operation of the anchorage. also in case of open-sea anchorage vulnerable to external force of certain conditions due to geographical location and topographical characteristics of the port, accidents are likely dragging anchor by typoon or suddenly strong wind and secondary accidents are concerned. This paper shows standard of limit external force to ensure the safety anchorage each of ship's size through review marine accidents on Pohang port, also it is determined to be used as a basic reference for anchoring safety and efficient anchorage management.

• Ocean and Polar Research
• /
• v.30 no.4
• /
• pp.379-399
• /
• 2008

Spatial-temporal variations in physiochemical water qualities (temperature, salinity, DO, SPM, POC and nutrients) of surface and bottom waters were investigated along the mid-western coastal area (Taean Peninsula to Gomso Bay) of Korea. Spatial distribution patterns of temperature and salinity were mostly controlled by the physical mixing process of freshwater from Geum River and/or Gyunggi Bay with nearby coastal water. A strong tidal front is formed off Taean Peninsula during spring and summer. Seasonal variations in nutrient concentrations, lower in spring and summer and higher in fall and winter, are primarily regulated by magnitude of phytoplankton occurrence rather than freshwater loadings into the bay. Based on seasonal and spatial variability of physicochemical parameters, water quality of the study area can be divided into four water masses; Gyunggi Bay-influenced Water Mass (GBWM), Geum River-influenced Water Mass (GRWM), Yellow Sea Bottom Cold Water Mass (YSBCWM) and Cheonsu Bay Water Mass (CBWM). Water quality of the GBWM (Taean Peninsula coastal area), which has relatively low salinity and high concentrations of nutrients, is strongly controlled by the Gyunggi Bay coastal water, which is under influence of the Han River freshwater. In this water mass, the mixed layer is always developed by strong tidal mixing. As a result, a tidal front is formed along the offshore boundary of the mixed layer. Such tidal fronts probably play an important role in the distribution of phytoplankton communities, SPM and nutrients. The GRWM, with low salinity and high nutrients, especially during the flood summer season, is closely related to physiochemical properties of the Geum River. During the flood season, nutrient-enriched Geum River water mass extends up to 60 km away from the river mouth, potentially causing serious environmental problems such as eutrophication and unusual and/or noxious algal blooms. Offshore (<$30{\sim}40m$ in water depth) of the study area, YSBCWM coupled with a strong thermocline can be identified in spring-summer periods, exhibiting abundant nutrients in association with low temperature and limited biological activity. During spring and summer, a tidal front is formed in a transition zone between the coastal water mass and bottom cold water mass in the Yellow Sea, resulting in intensified upwelling and thereby supplying abundant nutrients to the GBWM and GRWM. Such cold bottom water mass and tidal front formation seems to play an important role in controlling water quality and further regulating physical ecosystem processes along mid-western Korean coastal area.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2003.11a
• /
• pp.91-97
• /
• 2003

본 연구는 온라인 게임공간에서 게이머들이 어떻게 서로 다른 가치관과 행동 패턴을 드러내는지를 확인하고 이를 통해 온라인 게임세계의 문화를 이해하고 분석하기 위해 실시되었다. 전 세계에서 가장 많은 게이머들이 활동하고 있고, 한국과 일본에서 동시에 서비스되고 있는 온라인 게임인 〈리니지〉의 게이머들을 대상으로 온라인 설문조사를 실시하여 '라이프 스타일' 분석틀을 이용해서 이들이 게임공간에서 보이는 행동을 분류하였다. 글 결과 한국과 일본의 리니지 사용자들에게서 거의 유사한 세 가지 라이프스타일 패턴이 추출되었으며 한국과 일본에서 라이프스타일에 따른 행동 패턴이 일관적으로 나타나고 있음을 확인하였다. 도한 한국과 일본의 문화적 차이는 각 라이프스타일 프로파일의 극단성과 분포비율에 의해 반영되는 것으로 확인되었다. 일본의 탈사회적 게이머는 한국의 그것에 비해 더 극단적인 반면 전체 응답자 중에서 차지하는 비율이 적었고 게임 세계에서의 사회 경제적 위치도 낮았으며 한국에서는 비교적 적은 비율을 차지하던 싱글 플레이어 유형이 일본에서는 가장 많은 비중을 차지하는 것으로 나타났다. 또한 일본의 게이머들은 라이프스타일에 상관없이 대부분이 게임 공동체에 가입하는 반면 한국의 게이머들은 라이프스타일에 따라 공동체 참여율이 달랐지만 전체적인 참여율은 일본에 비해 높았다. 이러한 차이는 일본 게임세계에서 공동체 참여는 기본적인 의무인 반면 한국에서는 현실적인 이익과 직결된 활동임을 시사한다. 또한 게임몰입수준은 한국보다 일본의 리니지 게이머들이 높았다. 아시아 각 국에 한국에서 개발한 동일한 온라인 게임이 확산되어 있는 현황을 고려할 때, 온라인 게이머의 라이프스타일 척도는 한국과 일본뿐만 아니라 대만과 중국, 홍콩, 그리고 미국과 같은 리니지 게임이 서비스되는 모든 국가의 문화적 차이를 이해하고 과학적으로 분석할 수 있는 방법이 될 수 있을 것으로 기대된다. 의미를 되새기는 것으로 짧은 연구를 시작하겠다. 등은 활성 값이 70% 이상으로 퇴적물 독성이 상대적으로 낮았다. 이중나선 DNA 함량은 28.4 % - 49%로 대조군에 비해서 감소가 크다. 대부분의 정점이 대조군의 30% 내외로 정점 간의 차이는 크지는 않다. 그러나 다른 측정자료와 같이 정점 22에서 18%로 최소치를 나타내고, 정점 2, 12에서 20% 내외의 값을 보인다. 종합적으로 볼 때 오염물질의 유입이 크고, 광양제철 인근 정점 들이 모두 다른 정점에 비해서 낮아서, 퇴적물 독성이 높은 정점으로 조사되었다.hiwo의 광합성 능력은 낮은 농도들에서는 대조구와 유사하였으나, 5 $\mu\textrm{g}$/l의 높은 농도에서는 초기에 매우 낮은 광합성 능력을 보이다가 시간이 경과하면서 대조군보다 더 높은 경향을 나타냈다. 이러한 결과는 식물플랑크톤이 benso[a]pyrene의 낮은 농도에서 노출될 때는 이 물질을 탄소원으로 사용할 가능성이 있음을 시사한다. 본 연구의 결과들은 연안해역에 benso[a]pyrene과 같은 지속성 유기오염물질이 유입되었을 때 내정여부에 따라 식물플랑크톤 군집내 종 천이와 일차생산력에 크게 영향을 미칠 수 있음을 시사한다.TEX>5.2개)였으며, 등급별 회수율은 각각 GI(8.5%), GII(13.4%), GIII(43.9%), GIV(34.2%)로 나타났다.ments of that period left both in Japan and Korea. "Hyojedo" in Korea is supposed to have been influenced by the letter design. Asite- is also considered to have been "Japanese Letter Jobcheso." Therefore, the purpose of this study is to look into

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.4
• /
• pp.282-287
• /
• 2016

Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.

• Korean Journal of Ecology and Environment
• /
• v.33 no.4 s.92
• /
• pp.342-349
• /
• 2000

This paper demonstrates the influence of intensity of the monsoon on morpho-hydrological fluctuations in Taechung Reservoir during 1993${\sim}$1994. During the study, hydrological variables including rainfall, inflow, and discharge volume showed distinct contrast between 1993 and 1994. Interannaul differences in rainfall occurred during the monsoon in July${\sim}$August monsoon and influenced inflow, discharge, and water residence time (WRT). Total inflow in 1993 was four times greater than that of 1994, and summer inflow in 1993 was 8 times greater than summer 1994. Annual Mean WRT was 93.2 d in 1993 vs. 158.6 d in 1994 and the largest differences occurred between monsoons of 1993 and 1994. Morphometric variables reflected the interannual contrasts of hydrology, so that in 1993 surface area, total volume, shoreline development, and mean depth increased consistently from premonsoon to postmonsoon and over this same period in 1994 they decreased. This outcome indicates that the area of shallow littoral zones in 1993 was greater than in 1994. Also, the drainage area to surface area (D/L) at 80 m MSL was 60.7 which was much greater than values in Soyang and Andong reservoirs and natural lakes world-wide. The morpho-hydrodynamic conditions seemed to influence in-reservoir nutrient concentration which is one of the most important factors regulating the eutrophication processes. I believe, under the maximum hydrodynamic fluctuations in Korean waterbodies during the monsoon, applications of mass balance models to man-made lakes for assessments of external loading should be considered because the models can be used under the seasonally stable inflow and water residence time.

• Korean Journal of Remote Sensing
• /
• v.36 no.2_2
• /
• pp.263-275
• /
• 2020

In this study, DEMs (Digital elevation model) based on LIDAR, TanDEM-X and UAV (Unmanned Aerial Vehicle) are used to analyze topographic change of Gomso tidal flat during a few years. DEM from LIDAR data was observed at 2011 by KHOA (Korean hydrographic and oceanographic agency) and DEM based on TanDEM-X data was generated at Lee and Ryu (2017). UAV data was observed at KM and KH area of Gomso tidal flat. KM area was surveyed at MAY and AUG 2019, and KH area was surveyed at APR 2018 and MAY 2019. During research period, 2011 to AUG 2019, elevation of KM area is decreased 0.24 m in average, and Chenier is retreat to landward about 130 m. In KH area, elevation is increased 0.16 m in average during research period, 2011 to MAY 2019. It is expected that multi-platform remotely sensed data can help to study accurate topographic change of tidal flat.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.20 no.2
• /
• pp.83-90
• /
• 1984

The secular fluctuations of catches and fishing grounds of mackerals and the oceanographic conditions for the fishing grounds are examined by using the data of catches of mackerals by middle and large class purse-seiner during 1951 to 1981 and those of oceanographic observation carried out by Japan Meteorological Agency. The results are as follows; The fishing grounds of mackerals are respectively distributed at northeastern and southwestern areas from the central part of the East China Sea through every season of the studied years: 1968, 1974 and 1980. The narrow belt type of fishing grounds were formed inside of the Kuroshio in spring and winter of the three years. In summer mackeral species move northward and the fishing grounds are formed in the southern sea of Korea. In winter, however, mackeral species move southward and the fishing grounds are appeared in the Tsushima Current region. The dispersion of fishing grounds is generally larger in summer and smaller in spring, and especially it is the largest in summer in 1980. It seems that the concentration and dispersion of fishing grounds are related to the depth of thermocline and the position of horizontal temperature gradient in this area.

• Ocean and Polar Research
• /
• v.29 no.2
• /
• pp.135-153
• /
• 2007

Temporal (seasonal) and spatial distributions and variations of various physico-chemical factors (salinity, temperature, pH, DO, COD, SPM, POC, silicate, DIP, DIN) in surface and bottom waters were studied in the coastal environment with typical macro-tidal range and monsoonal weather condition, Gyeonggi Bay, west coast of Korea. Spacial distribution patterns of these factors were generally similar to each other, and appeared to be inversely related to the distribution pattern of salinity, suggesting that water quality of the study area was primarily controlled by the physical mixing process of Han-River freshwater with nearby coastal seawater. During flooding season, silicate- and nitrogen-rich Han River water directly flowed into offshore as far as $20\sim30\;km$ from the river mouth, probably causing serious environmental problems such as eutrophication and unusual and/or noxious algal bloom, etc. Except the surface water during summer flooding season, high concentrations of nutrients appeared generally in dry season, whereas low values in spring, possibly because of the occurrence of spring phytoplankton bloom. On the other hand, nutrient flux through the estuary seems to be primarily depending on river discharge, sewage discharge and agricultural activities, especially during the rainy season. Also, nutrients in this coastal waters are considered to be supplied from the sediments of tidal-flats, which developed extensively around the Han-River mouth, especially during fall and winter of dry and low discharge seasons, possibly due to the stirring of tidal flat sediments with highly enriched pore-water nutrients by storm. And also, COD and DIN concentrations in the study area consistently increased during the last 20 years, probably because of agricultural activities and increasing discharge of industrial and domestic wastes.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.19 no.4
• /
• pp.329-335
• /
• 2007

The eye measurement to observe the sea surface condition and estimate the wave height has been used in the open sea or the ship. The experts in the eye estimation can measure the wave height very accurately. The Beaufort wind scale is most widely used as a standard index of the eye measurement. However, more definite reference data such as the representative images by each wave heights must be necessary because the appearances and explanations in the Beaufort wind scale are not enough to understand the sea surface condition far the researcher and the public. The modern field data acquisition technique has been developed to measure wave heights, ocean weather data and even images of the sea surface in real-time. In this study, the wireless field image transmitting system for wave heights and images is installed in the real-time ocean measurement system of Chodo light tower near Sokcho city in South Korea. The wave heights and surface images acquired from the real time system in the field are compared with explanations of the Beaufort wind scale. The wave heights and images measured with the precision ultrasonic wave sensor and the scientific sea surface image transmitting system should be helpful to obtain more precise and definite information than the data from the Beaufort wind scale.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.3
• /
• pp.202-208
• /
• 2009

In order to understand the circulation of nutrient between muddy tidal flat and the surrounding coastal area, tidal time-scale variations in nutrient concentrations were seasonally investigated at the entrance of Hampyeong Bay. The results show that the temperature was higher in ebb tide and lower in flood tide during the summer, but it was lower in ebb tide and higher in flood tide during the autumn/winter. The salinity was higher in flood tide and lower in ebb tide during the summer/winter because of the inflow of external sea water resulting from the increase in the tide level. By contrast, the salinity was lower in flood tide and higher in ebb tide during the autumn. Salinity difference was lower than 0.3 psu between flood tide and ebb tide during survey period. Meanwhile, all nutrient concentrations observed in Hampyeong Bay was lower in flood tide and higher in ebb tide during the summer, and by contrast, it was higher in flood tide and lower in ebb tide during the winter. Characteristically, no clear variation of concentrations was found depending on the tide level during the autumn. This tidal variations imply that the muddy tidal flat of Hampyeong Bay supplies nutrients to the seawater in summer and removes nutrient from the seawater in winter. During tidal cycle, seasonal variation of nutrient concentration in seawater is considered as the result of complex interactions between the mud flat and external sea water.